* {
    margin: 0;
    padding: 0;
}

body {
    /* 100%窗口高度 */
    height: 100vh;
    /* 弹性布局 居中 */
    display: flex;
    justify-content: center;
    align-items: center;
    /* 渐变背景 */
    background: linear-gradient(200deg, #e3c5eb, #a9c1ed);
    /* 溢出隐藏 */
    overflow: hidden;
}

.login {
    width: 500px;
    border: 1px solid #4d4d4d;
    margin: 100px auto;
    border-radius: 4px;
    box-shadow: 5px 5px 5px rgb(98, 89, 110);
    padding: 20px 40px;
    background-color: rgba(0, 0, 0, .1);
}

.login>img {
    position: absolute;
    display: block;
    width: 55px;
    height: 55px;
    box-shadow: 18px 18px 30px rgba(0, 0, 0, 0.2);
    transition: all .2s ease-out;
}

/* ,
        -18px -18px 30px rgba(33, 30, 32, 1) */
.login>img:hover {
    cursor: pointer;
    box-shadow: 0 0 0 rgba(0, 0, 0, 0.2),
        0 0 0 rgba(135, 206, 235, .8);
}

/* ,
        18px 18px 30px rgba(0, 0, 0, 0.1),
        -18px -18px 30px rgba(33, 30, 32, 1) */
.login h2 {
    text-align: center;
}

.login .anniu {
    text-align: center;
}

/* 背景 */
ul li {
    position: absolute;
    border: 1px solid #fff;
    background-color: #fff;
    width: 30px;
    height: 30px;
    list-style: none;
    opacity: 0;
}

.square li {
    top: 40vh;
    left: 60vw;
    /* 执行动画：动画名 时长 线性的 无限次播放 */
    animation: square 10s linear infinite;
}

.square li:nth-child(2) {
    top: 80vh;
    left: 10vw;
    /* 设置动画延迟时间 */
    animation-delay: 2s;
}

.square li:nth-child(3) {
    top: 80vh;
    left: 85vw;
    /* 设置动画延迟时间 */
    animation-delay: 4s;
}

.square li:nth-child(4) {
    top: 10vh;
    left: 70vw;
    /* 设置动画延迟时间 */
    animation-delay: 6s;
}

.square li:nth-child(5) {
    top: 10vh;
    left: 10vw;
    /* 设置动画延迟时间 */
    animation-delay: 8s;
}

.circle li {
    bottom: 0;
    left: 15vw;
    /* 执行动画 */
    animation: circle 10s linear infinite;
}

.circle li:nth-child(2) {
    left: 35vw;
    /* 设置动画延迟时间 */
    animation-delay: 2s;
}

.circle li:nth-child(3) {
    left: 55vw;
    /* 设置动画延迟时间 */
    animation-delay: 6s;
}

.circle li:nth-child(4) {
    left: 75vw;
    /* 设置动画延迟时间 */
    animation-delay: 4s;
}

.circle li:nth-child(5) {
    left: 90vw;
    /* 设置动画延迟时间 */
    animation-delay: 8s;
}

/* 定义动画 */
@keyframes square {
    0% {
        transform: scale(0) rotateY(0deg);
        opacity: 1;
    }

    100% {
        transform: scale(5) rotateY(1000deg);
        opacity: 0;
    }
}

@keyframes circle {
    0% {
        transform: scale(0) rotateY(0deg);
        opacity: 1;
        bottom: 0;
        border-radius: 0;
    }

    100% {
        transform: scale(5) rotateY(1000deg);
        opacity: 0;
        bottom: 90vh;
        border-radius: 50%;
    }
}